Analysis of an Ecological Flow Regime during the Ctenopharyngodon Idella Spawning Period Based on Reservoir Operations
, Shaoqian Pei 1,2, Liqiang Yao 3, Wei Wen 4, Liang Yi 4, Jianzhong Zhou 1,2 and Lingyun Tang 1,2Round 1
Reviewer 1 Report
Dear Authors,
Major quality improvement are needed to enable a publication in a journal like Water. However since the research is well performed, the improvement of the paper I doable. I make some suggestions to help you.
Abstract
12: “Fish habitat is an important part of riverine ecosystems”. Please reformulate. Do you mean that fish habitat studies are important to better understand the consequence of river modifications. Or do you mean that Fish habitat loss is a major issue in modified river system, oder something else?
13-15. I strongly disagree with the statement. Habitat models were already used for lot more than that.
16: “Qingshui River of China as a case study to A) INVESTIGATE EFFECT OF IN- AND OUTFLOW OF RESERVOIR ON FISH HABITATS, AND B) IDENTIFY THE BEST INTEGRATIVE MANAGMEMENT MEASURE IN THE CASE OF THE XUANWEI RESERVOIR”
19:“a fuzzy logic-based habitat model has been developed TO IDENTIFY BASELINE CONDITION TO ACHIEVE SUITABLE HABITAT FOR CI SPAWNING ACTIVITESfor evaluating suitable ecological flow of CI spawning”
24: “The weighted usable area WUA and hydraulic habitat suitability WERE CALCULATED FOR under 64 SCENARIOS SIMULATING schemes comprised of different reservoir in- AND OUTflows and discharges were calculated and analyzed to obtain a suitable ecological flow range.
26-29: “According to the fuzzy logic-based habitat model in this paper, a more reasonable ecological flow range that takes into account hydraulic factors such as water temperature, velocity and water depth can be given, which provides reference and guidance for the ecological scheduling of fish protection.” This is not your conclusion. You concluded that the method you used was suitable to identify the best management scenario, and you conclude what was the best scenario for your case site.
Introduction:
33: Reservoir are not “natural resource”. Reservoir are grey infrastructure collecting water, that is a natural resource.
34: that it is not an exhaustive liste of the negative effect of reservoir. Please indicate it the text.
36: “Furthermore, the RESULTING discharge process after the construction of reservoir change THE environmental RIVER characteristics AND RELATED fish habitats QUALITY AND QUALiTY“ (see Zingraff-Hamed, A.; Noack, M.; Greulich, S.; Schwarzwälder, K.; Pauleit, S.; Wantzen, K.M. (2018) Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality. Water (10) 374.)
38: “AS A RESULT, RESERVOIR CONSTRUCTION MAY CAUSE which could decrease of the BIOLOGICAL abundance of fish species and even led to the disappearance of some fish spawning grounds”
33-40: since you did not present the interest of studying fish habitat (which should be the second paragraph of the introduction) please stay in the first paragraph of the introduction general. Reservoir impact all aquatic and terrestrial riparian species, not just fishes. In this paragraph I do expect some number about the global reservoir construction trend and why are we building reservoir.
41: “Fish habitat is an important component of riverine ecosystems.” Please develop and detail why it is important to study fish habitat. Namely, fish are a powerful indicator species of the river health.
43 „At present, there are several classical approaches have beINGen used to estimate ecological flow
42-60: very good. But what about the new modeling procedure CASiMiR?
61-62: It is very depending of the specie you consider. But the substrat play an important role too. For some species, a high oxygen concentration is crucial. Give some info on the specie you are talking about. Or stay general, say that temperature is ONE of the most important physical parameter that are interesting to study, and why. You will present the whole number of parameter you are studying in the Method section.
76-83: Advantage of fuzzy method, should be include in the paragraph you are presenting the different modeling procedures
You should talk in the introduction about integrative flow management. Because it is what you are studying and I had to read 12 pages before I get it.
Study area and species:
Minor change may be require, but I will come back to it in the second round.
We need a hydrograph, a graph of yearly temperature
143-146: be in the introduction
147: don’t mention results in the methods. Suppress or relocate in the abstract
221-222: add citation
224: add citation
Methods:
Missing a part about the analysis of the model outcomes WUA and HHS. Pairwise comparison?
Results:
How react the fish to the flow modification aiming at change water temperature?
Discussion:
Could you please put the final results of the different scenario 80 m3/s, 100 m3/s, 120 m3/s, 140
432 m3/s and 160 m3/s in a table and indicating when it is beneficial or not for the spawning activities and why.
In the discussion part, the meaning of the results are explained. However, a real discussion of this results based on the international literature is still missing.
Conclusion
453: “has been developed for evaluating the EFFECT OF inflow and discharge of the Xuanwei Reservoir on the spawning habitat suitability of Ctenopharyngodon idella (CI) in Qingshui River.
464: “an important role in CONSERVING protecting fish habitats”
464: “Further works should be focused“
Please make a like with other integrative or ecological reservoir management
Author Response
Dear reviewer,
Thanks very much for giving us constructive suggestions which would help us to improve the quality of the paper. Here we submit the revised version of our manuscript with the title “Analysis of an ecological flow regime during the Ctenopharyngodon idella spawning period base on reservoir operations”, which has been modified according to the reviewers’ suggestions. If there is any question about this paper, please don’t hesitate to let us know.
Sincerely yours,
Hui Qin, Associate Professor
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The following is a point-to-point response to your comments.
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(1) Abstract
12: “Fish habitat is an important part of riverine ecosystems”. Please reformulate. Do you mean that fish habitat studies are important to better understand the consequence of river modifications? Or do you mean that Fish habitat loss is a major issue in modified river system, or something else?
13-15. I strongly disagree with the statement. Habitat models were already used for lot more than that.
16: “Qingshui River of China as a case study to A) INVESTIGATE EFFECT OF IN- AND OUTFLOW OF RESERVOIR ON FISH HABITATS, AND B) IDENTIFY THE BEST INTEGRATIVE MANAGMEMENT MEASURE IN THE CASE OF THE XUANWEI RESERVOIR”
19:“a fuzzy logic-based habitat model has been developed TO IDENTIFY BASELINE CONDITION TO ACHIEVE SUITABLE HABITAT FOR CI SPAWNING ACTIVITES for evaluating suitable ecological flow of CI spawning”.
24: “The weighted usable area WUA and hydraulic habitat suitability WERE CALCULATED FOR under 64 SCENARIOS SIMULATING schemes comprised of different reservoir in- AND OUT flows and discharges were calculated and analyzed to obtain a suitable ecological flow range.
26-29: “According to the fuzzy logic-based habitat model in this paper, a more reasonable ecological flow range that takes into account hydraulic factors such as water temperature, velocity and water depth can be given, which provides reference and guidance for the ecological scheduling of fish protection.” This is not your conclusion. You concluded that the method you used was suitable to identify the best management scenario, and you conclude what was the best scenario for your case site.
Answer:
Thank you very much for the comments on the paper.
(1) Line 12: The meaning of the 12th line of the article is difficult to understand. It has now changed as required. “Fish habitat research is important to better understand the consequence of reservoir construction on river ecosystems.”
(2) Line 13-15: The 13-15 line of the article was re-described. It has now changed as required. “In the past, the habitat model has been studied by a large number of scholars as a hot issue. With the development of research, habitat modeling, research target species and habitat hydraulic factors can be further explored.”
(3) Line 16, 19 and 24: The description of the line 16, line 19 and line 24 of statements has been modified according to your requirements.
(4) Line 26-29: The conclusions of the article in the abstract were rewritten on lines 26-29. It has now changed as required. “The results show that the ecological flow for fish spawning can be satisfy satisfied basically demand when the reservoir inflow is greater than 60 m3/s and the reservoir outflow is greater than 100 m3/s. The habitat ecological suitability is the best when the reservoir outflow is 120 m3/s. According to the habitat modeling method in this paper, a more reasonable and reliable ecological flow range can be obtained, which provides the best scenario for water resources planning and management in Qingshui River Basin.”
(2) Introduction:
33: Reservoir are not “natural resource”. Reservoir are grey infrastructure collecting water, that is a natural resource.
34: that it is not an exhaustive list of the negative effect of reservoir. Please indicate it the text.
36: “Furthermore, the RESULTING discharge process after the construction of reservoir change THE environmental RIVER characteristics AND RELATED fish habitats QUALITY AND QUALiTY“ (see Zingraff-Hamed, A.; Noack, M.; Greulich, S.; Schwarzwälder, K.; Pauleit, S.; Wantzen, K.M. (2018) Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality. Water (10) 374.)
38: “AS A RESULT, RESERVOIR CONSTRUCTION MAY CAUSE which could decrease of the BIOLOGICAL abundance of fish species and even led to the disappearance of some fish spawning grounds”.
33-40: since you did not present the interest of studying fish habitat (which should be the second paragraph of the introduction) please stay in the first paragraph of the introduction general. Reservoir impact all aquatic and terrestrial riparian species, not just fishes. In this paragraph I do expect some number about the global reservoir construction trend and why are we building reservoir.
41: “Fish habitat is an important component of riverine ecosystems.” Please develop and detail why it is important to study fish habitat. Namely, fish are a powerful indicator species of the river health.
43: At present, there are several classical approaches have beING en used to estimate ecological flow.
42-60: very good. But what about the new modeling procedure CASiMiR?
61-62: It is very depending of the specie you consider. But the substrate play an important role too. For some species, a high oxygen concentration is crucial. Give some info on the specie you are talking about. Or stay general, say that temperature is ONE of the most important physical parameter that are interesting to study, and why. You will present the whole number of parameter you are studying in the Method section.
76-83: Advantage of fuzzy method, should be include in the paragraph you are presenting the different modeling procedures.
You should talk in the introduction about integrative flow management. Because it is what you are studying and I had to read 12 pages before I get it.
Answer:
Thank you for your comments, we have revised and rewritten the introduction framework after consideration.
(1) Line 33: Line 33 has certain errors in the description of the reservoir. It has now changed as required. “As a water conservancy project that prevent or control flood and regulates water flow, the reservoir plays an increasingly important role in social and economic development.”
(2) Line 34: The negative effect caused by the construction of the reservoir in the 33rd line are not exhaustive. It has now changed as required. “These effects are mainly manifested in: 1) blocking the migration path of fish to make it impossible to complete its life history process, resulting in a decline in genetic diversity of fish populations [2]; 2) affecting sediment transport, resulting in sedimentation at the bottom of the reservoir and river blockage [3]; 3) affecting nitrogen, phosphorus and other substances migration, thereby inducing eutrophication [4]; 4) leading to a decrease in the temperature of the outflow during the spawning period of the fish, which delays the breeding season and thus affects the growth of the individual born in the current year.”
[2] A T Piper, P J Rosewarne, R M Wright, P S Kemp. The impact of an Archimedes screw hydropower turbine on fish migration in a lowland river. Ecological Engineering, 2018, 118: 31-42.
[3] M Zhang, W M Wu. A two dimensional hydrodynamic and sediment transport model for dam break based on finite volume method with quadtree grid. Applied Ocean Research, 2011, 33(4): 297-308.
[4] Y Wang, X Lei, X Wen, G Fang, Q Tan, Y Tian, C Wang, H Wang. Effects of damming and climatic change on the eco-hydrological system: A case study in the Yalong River, southwest China. Ecological Indicators, 2018, 7: 1-12.
(3) Line 36, 38 and 43: The description of the line 36, line 38 and line 43 of statements has been modified according to your requirements. At the same time, the citations have been added.
(4) Line 33-40: We rewrote the end of the first paragraph of the introduction and introduced reservoir construction and water management planning. “Therefore, predicting reservoir inflow and developing reasonable reservoir discharge measures is crucial for protecting and restoring the impacted downstream fish habitats.”(Delete content) “With the rapid development of the economy, the problem of energy shortage is becoming more and more serious. Hydropower is attracting more and more country attention as a clean and sustainable energy source. In recent years, more and more reservoirs have been built. According to statistics, more than 100,000 reservoirs have been built in China with more than 100,000 m3 of storage capacity. Watershed water resources management and planning and the development of rational flow plans also require in-depth research and exploration.” (Add content)
(5) Line 41: Based on your comments, we detail the significance of fish habitat research. “Fish are a common indicator of aquatic habitat richness [6, 7]. Its habitat includes the waters necessary to complete the entire life history process, such as spawning grounds, feeding grounds, wintering grounds, and migratory passages connecting waters of different life stages [8, 9]. Fish habitats not only provide living space for fish, but also provide all environmental factors such as water temperature, substrate, flow rate, pH value, and dissolved oxygen that satisfy the survival, growth and reproduction of fish.”
[6] S Birk, W Bonne, A Borja, S Brucet, A Courrat, S Poikane, A Solimini, W Bund, N Zampoukas, D Hering. Three hundred ways to assess Europe's surface waters: An almost complete overview of biological methods to implement the Water Framework Directive. Ecological Indicators, 2012, 18: 31-41.
[7] J Pander, J Geist. Ecological indicators for stream restoration success. Ecological Indicators, 2013, 30: 106-118.
[8] M Bishop, J H Eiler. Migration patterns of post-spawning Pacific herring in a subarctic sound. Deep Sea Research Part II: Topical Studies in Oceanography, 2018, 147: 108-115.
[9] S Frantzen, A Maage, A Duinker, K Julshamn, S A Iversen. A baseline study of metals in herring (Clupea harengus) from the Norwegian Sea, with focus on mercury, cadmium, arsenic and lead. Chemosphere, 2015, 127: 164-170.
(6) Line 42-46: In order to ensure the integrity of the model introduction, we have added a new modeling procedure CASiMiR. “The Computer Aided Simulation Model for Instream Flow Requirements (CASiMiR) is a habitat simulation tool for aquatic organisms with a focus on fish and macroinvertebrates [26]. It uses a multivariate fuzzy-logical approach to link abiotic attributes with habitat requirements of aquatic species, resulting in a habitat suitability index (HSI) [26]. The fuzzy model takes into account the uncertainties of habitat hydraulics variables and enable expressing non-linear relations between habitat hydraulics variables in a transparent manner [27]. It uses the three physical characteristics of rivers that allow for the determination of the quality of habitats for fish species: velocity, water depth and water temperature [28]. Each parameter is classified by an overlapping membership function described by a fuzzy language. Since the boundaries of two consecutive fuzzy sets are overlapping, an object may partially belong to two consecutive fuzzy sets [29]. The expert knowledge is embedded in fuzzy if–then rules to determine the relationship between these physical parameters and biological responses, and to define fuzzy rules in combination. It use language descriptions such as ‘low’, ‘moderate’ or ‘high’ for the quantification of hydraulics variables and combines the knowledge of aquatic ecology experts to translate these descriptions into a data processing framework [30].”
[26] A Zingraff-Hamed, M Noack, S Greulich, K Schwarzwälder, S Pauleit, K Wantzen. Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality. Water, 2018, 10(4): 374.
[27] I Boavida, V Dias, M T Ferreira, J M Santos. Univariate functions versus fuzzy logic: Implications for fish habitat modeling. Ecological Engineering, 2014, 71: 533-538.
[28] A M Mouton, J D Alcaraz-Hernández, B De Baets, P L M Goethals, F Martínez-Capel. Data-driven fuzzy habitat suitability models for brown trout in Spanish Mediterranean rivers. Environmental Modelling & Software, 2011, 26(5): 615-622.
[29] P Zhang, Z Yang, L Cai, Y Qiao, X Chen, J Chang. Effects of upstream and downstream dam operation on the spawning habitat suitability of Coreius guichenoti in the middle reach of the Jinsha River. Ecological Engineering, 2018, 120: 198-208.
[30] S Fukuda, B De Baets, A M Mouton, W Waegeman, J Nakajima, T Mukai, K Hiramatsu, N Onikura. Effect of model formulation on the optimization of a genetic Takagi–Sugeno fuzzy system for fish habitat suitability evaluation. Ecological Modelling, 2011, 222(8): 1401-1413.
(7) Line 61-62: Fish habitats not only provide living space for fish, but also provide all environmental factors such as water temperature, substrate, flow rate, pH value, and dissolved oxygen that satisfy the survival, growth and reproduction of fish. The main research object of this paper is grass carp, and flow and water temperature are one of the two main influencing factors. We have made corresponding changes in the paper. “Fish habitats are mainly affected by the hydrological conditions of the river, where flow and water temperature are considered to be the one of the two main important factors affecting fish spawning [10]. Water temperature plays an important role in the spawning and hatching of fish.”
[10] R Benjankar, D Tonina, J A McKean, M M Sohrabi, Q Chen, D Vidergar. Dam operations may improve aquatic habitat and offset negative effects of climate change. Journal of Environmental Management, 2018, 213: 126-134.
(8) Line 76-83: Based on your requirements, we include the advantages of the fuzzy method in the different modeling procedures.
(9) Regarding the issue of integrative flow management, we have added and emphasized in the introduction. The first paragraph of the introduction adds new content. “Watershed water resources management and planning and the development of rational flow plans also require in-depth research and exploration.” The last part of the introduction adds new content. “Therefore, this paper uses fuzzy models to explore the effects of water temperature, velocity, water depth and other hydraulic factors on fish habitat. Through the simulation results of habitat suitable ecological flow, the paper finally gives the best flow management scheme suitable for the study area.” “This study aimed to: 3) By simulating various inflow and outflow conditions of reservoirs, a functional relationship between flow and habitat suitability is established, which provides the best management plan for water resources planning and construction.”
(3) Study area and species:
Minor change may be require, but I will come back to it in the second round.
We need a hydrograph, a graph of yearly temperature.
143-146: be in the introduction.
147: don’t mention results in the methods. Suppress or relocate in the abstract.
221-222: add citation.
224: add citation.
Answer:
Thank you for your suggestions to make the content of the article more complete.
(1) Line 143-146: We have added a new reservoir inflow and water temperature graph of the study area. At the same time, we explained the contents of the figure. “According to the data of Duyun hydrological station in the study area, the data of reservoir inflow and water temperature of typical years are obtained: wet year (75% guarantee rate of runoff), normal year (50% guarantee rate of runoff) and dry year (25% guarantee rate of runoff). According to the inflow data of the reservoir, the annual large-scale flow is mainly concentrated from mid-May to early-July. The highest water temperature in the year occurred in August, and the lowest water temperature occurred in February. According to the survey, the spawning period of Ctenopharyngodon idella in the study area is mostly concentrated from mid-May to mid-July. The suitable flow range and suitable water temperature range determine the spawning period of the fish. The annual reservoir inflow rate and water temperature of the study area is shown in Figure 2.”
Figure 2. A graph of annual reservoir inflow and water temperature in study area.
(2) Line 147: Thank you for your comments, we have deleted this sentence. “The research results provide the basis for constructing reservoir ecological scheduling of fish protection.”
(3) Line 221-222: Thank you for your suggestions. We have added new citation.
[41] J H Purba, D T S Tjahyani, A S Ekariansyah, H Tjahjono. Fuzzy probability based fault tree analysis to propagate and quantify epistemic uncertainty. Annals of Nuclear Energy, 2015, 85: 1189-1199.
[42] X Liu, X Feng, W Pedrycz. Extraction of fuzzy rules from fuzzy decision trees: An axiomatic fuzzy sets (AFS) approach. Data & Knowledge Engineering, 2013, 84: 1-25.
(4) Line 224: Thank you for your suggestions. We have added new citation.
[43] S Fukuda. Consideration of fuzziness: Is it necessary in modelling fish habitat preference of Japanese medaka (Oryzias latipes)? Ecological Modelling, 2009, 220(21): 2877-2884.
[44] E Van Broekhoven, V Adriaenssens, B De Baets, P F M Verdonschot. Fuzzy rule-based macroinvertebrate habitat suitability models for running waters. Ecological Modelling, 2006, 198(1-2): 71-84.
(4) Methods:
Missing a part about the analysis of the model outcomes WUA and HHS. Pairwise comparison?
Answer:
We added analysis and comparison of WUA and HHS to the methods and results of this paper.
The best flow management scenario is determined by comparing and analyzing the simulation results under WUA and HHS for each scenario. The larger the WUA value, the larger total habitat weighted usable area for fish spawning. Larger WUA value is more favorable for fish spawning. HHS is a normalized value between 0 and 1. The larger the HHS value, the larger the proportion of habitats area for fish spawning. Larger HHS value is more favorable for fish spawning.
The comparison between WUA and HHS is mainly as follows: 1) The effect of different outflow on WUA and HHS for the same reservoir inflow. Exploring the influence of water temperature, velocity and water depth on fish spawning. 2) The effect of the WUA and HHS when the reservoir inflow is equal to outflow. 3) Determine the suitable ecological flow range based on 64 scenarios.
The comparison between WUA and HHS provides the best management scenario for study area.
(5) Results:
How react the fish to the flow modification aiming at change water temperature?
Answer:
For the question you asked, we have added new content to the result of the article (4.3 Suitable ecological flow calculation).
“The effects of water temperature and flow rate on fish spawning were studied by designing different inflow and outbound flow scenarios. According to the annual reservoir inflow and water temperature in the study area, the fish spawning period mainly occurs from mid-May to mid-July. During this period, the water temperature and flow can meet the appropriate spawning conditions. In different scenarios, the relatively large outflow will make the water temperature lag time shorter, and the water temperature suitable for spawning can be reached more quickly. The water temperature and flow that meet the spawning requirements are larger in the overlap interval in the figure (Figure 2. A graph of annual reservoir inflow and water temperature in study area), so the longer the suitable spawning period of the fish, which is more conducive to fish breeding. Lower flow delay the water temperature of the fish for spawning. When the water temperature reaches the suitable water temperature, the flow may not meet the spawning conditions, which makes the suitable water temperature and the suitable flow do not coincide or coincide with each other for a short time (which can be expressed as a shortened spawning period in the Figure 2). Inducing fish spawning is the common result of both water temperature and flow. The model established in this paper considers these two aspects comprehensively and strives to obtain the best scenario.”
Table 2 shows the time taken to reach suitable ecological water temperature under different inflow and outflow scenarios. Table 3 shows hydraulic habitat suitability (HHS) under different inflow and outflow scenarios. The comparison shows the react of fish to the flow modification aiming at change water temperature. It can be seen from the results in Table 3 that an appropriate increase in the outflow will increase HHS. However, excessive flow may result in greater velocity in the habitat and excessively high water level in the local section, resulting in a decrease in HHS. Further explanation is that the induction of fish spawning is a common result of both water temperature and flow. The significance of the model research established in this paper seeks to get the best flow management scenario.
(6) Discussion:
Could you please put the final results of the different scenario 80 m3/s, 100 m 3/s, 120 m3/s, 140 m3/s and 160 m3/s in a table and indicating when it is beneficial or not for the spawning activities and why.
In the discussion part, the meaning of the results are explained. However, a real discussion of this results based on the international literature is still missing.
Answer:
(1): According to the results of WUA and HHS in the conclusion, 120 m3/s is relatively a suitable fish spawning flow. This paper wants to further discuss the impact of different outflows on WUA when the reservoir inflow is 120 m3/s. The large WUA value indicates that the larger total habitat weighted usable area for fish spawning, which is more favorable for fish spawning. As the outflow increases, when the outflow is greater than 120 m3/s, the habitat area suitable for fish spawning is gradually reduced, which is almost the same as the result reflected in HHS. 120 m3/s is relatively a best flow scenario for study area.
(2): Thank you for your comments. We have not done enough in the discussion section and now we have added it in 4.4.2 future work.
“With the development of the economy, more and more reservoirs have been built in China, and the problem of ecological habitats has received more and more attention. At the same time, watershed management and planning have made fish habitats an important conservation target.
This paper mainly considers the impact of flow management measures on the fish habitat after reservoir construction. Compared with the previous habitat model, the main highlights are: 1) This paper considers the thermal stratification of reservoirs and analyzes the important influence of the hysteresis of the water temperature on the spawning of fish in habitats. 2) In this paper, a fuzzy logic-based habitat suitability model is established to evaluate the influence of hydraulic factors such as water temperature, velocity and water depth on the suitability of fish habitat. 3) By simulating a variety of different reservoir inflow and outflow conditions, the functional relationship between flow and habitat suitability is established, which provides a certain guiding significance for reservoir ecological operation.
However, there are still some shortcomings in the current research, and further research will be carried out. 1) Fish habitats not only provide living space for fish, but also provide all environmental factors such as water temperature, substrate, flow rate, pH value, and dissolved oxygen that satisfy the survival, growth and reproduction of fish. The impact of various hydraulic factors on fish habitats will be considered in the future. 2) In addition to Ctenopharyngodon idellus in the study area, other economically valuable local fish will be considered as research protection targets. Habitat models that consider multiple species will be established in the future. 3) The current research is only for the fish spawning period, and the whole life cycle of the fish will be considered in the future, including: the hydraulic conditions of the feeding ground, the spawning ground and the wintering ground.”
(7) Conclusion
453: “has been developed for evaluating the EFFECT OF inflow and discharge of the Xuanwei Reservoir on the spawning habitat suitability of Ctenopharyngodon idella (CI) in Qingshui River.
464: “an important role in CONSERVING protecting fish habitats”.
464: “Further works should be focused”.
Answer:
(1) Line 453 and 464: The description of the line 453 and line 464 of statements has been modified according to your requirements.
Reviewer 2 Report
"Analysis of an ecological flow regime during the fish spawning period base on reservoir operations" is the title of a paper focusing on the Grass Carp and using similation models to produce good-looking graphics that are intersting a first glance however, the paper is very difficult to read. It is difficult primarily due to the poor effort to develop the English narrative, but not jus this. The paper has a very mechanistic and poorly developed holistic approach. It requires much work to interpret this. Also the title and objectives should state Grass Carp specifically. The whole paper is a localized account that should be made clear. With much effort it can be improved.
Author Response
Dear reviewer,
Thanks very much for giving us constructive suggestions which would help us to improve the quality of the paper. Here we submit the revised version of our manuscript with the title “Analysis of an ecological flow regime during the Ctenopharyngodon idella spawning period base on reservoir operations”, which has been modified according to the reviewers’ suggestions. If there is any question about this paper, please don’t hesitate to let us know.
Sincerely yours,
Hui Qin, Associate Professor
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The following is a point-to-point response to your comments.
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(1) "Analysis of an ecological flow regime during the fish spawning period base on reservoir operations" is the title of a paper focusing on the Grass Carp and using similation models to produce good-looking graphics that are interesting a first glance however, the paper is very difficult to read. It is difficult primarily due to the poor effort to develop the English narrative, but not just this. The paper has a very mechanistic and poorly developed holistic approach. It requires much work to interpret this. Also the title and objectives should state Grass Carp specifically. The whole paper is a localized account that should be made clear. With much effort it can be improved.
Answer:
Thank you very much for the comments on the paper.
(1) In order to more clearly show the overall structure of this paper, we added a section for the description before the model was built. At the same time, we have made a lot of changes to the abstract and the introduction, and more clearly explain the writing ideas of this paper.
In the abstract, in order to highlight the purpose of the study, the expression was re-presented. “This paper takes the Ctenopharyngodon idella (CI) in Xuanwei Reservoir on the Qingshui River of China as a case study to A) Investigate effect of in-and outflow of reservoir on fish habitat, and B) Identify the best integrative management measure in the case of the Xuanwei reservoir.”
At the same time, the results and conclusions have been revised. “The results show that the ecological flow for CI spawning can be satisfy satisfied basically demand when the reservoir inflow is greater than 60 m3/s and the reservoir outflow is greater than 100 m3/s. The habitat ecological suitability is the best when the reservoir outflow is 120 m3/s. According to the habitat modeling method in this paper, a more reasonable and reliable ecological flow range can be obtained, which provides the best scenario for water resources planning and management in Qingshui River Basin.”
The new add content to the methods of this paper is (3.1 model framework): “In this paper, the ctenopharyngodon idella (CI) in the study area was used as the target species to study the flow and water temperature effects of ctenopharyngodon idella during spawning. This paper specifically analyzes three main factors affecting the spawning of CI: velocity, water depth and water temperature. Two hydrodynamic models were used to simulate the hydraulic conditions of reservoir and the downstream habitats of reservoir. MIKE21 simulates the spatial distribution of velocity and water depth under different flows in habitat. CE-QUAL-W2 simulates the water temperature stratification of reservoirs under different inflows and outflows. The simulation results of velocity, water depth and water temperature were used to construct a fuzzy model to comprehensively analyze the effects of three factors on CI spawning. The simulation results of the fuzzy logic-based habitat suitability model are analyzed and evaluated by WUA and HHS, and the best flow management scenario in the study area is finally obtained. The overall framework of the habitat model is shown in Figure 3.” (Figure 3. A graph of habitat model framework)
(2) Thank you for your comments, we highlighted the target species in this paper. We have revised the title of the article. “Analysis of an ecological flow regime during the Ctenopharyngodon idella spawning period base on reservoir operations”. At the same time, in the introduction and methods, this paper focus on the target species (Grass Carp) in the study area.
(3) Finally, thank you for your suggestions on the language of this paper. We have reworked the language of this paper to remove some of the less commonly used words.
Author Response File: 
Author Response.doc
Reviewer 3 Report
In my manuscript, I have two copies of the text, with a little chaos on references and numbers, please, resolve that. There is some text in Chinese in the second copy; I believe that it is a preliminary document.
The paper is interesting and, in my opinion, worthy to be published. However, there are a lot of little mistakes to arrange, and some general issues to resolve. In general, I believe that text is too extensive. Explanations about models and fuzzy logic are very detailed, and it is not necessary. Discussion, in the same way, is very too extensive, you can reduce that.
Some minor changes in the text:
Line 3: scientific names should be in italics. Review that in all the text.
Lines 17, 20, 21 26 and 27: avoid the use of abbreviations on the abstract.
Lines 46-47: as support of this, you can use any references as the following paper:
Miranda, R., Martínez-Lage, J., Molina, J., Oscoz, J., Tobes, I., Vilches, A., 2012. Effects of stress controlled loading of a reservoir on downstream fish populations in a Pyrenean river. Environ. Eng. Manag. J. 11, 1125–1131.
Lines 52-53: this sentence needs a reference.
Line 55: I am not English native, but I believe that this sentence should be "Fishes are a common indicator"
Lines 62-63: Delete “Water temperature plays an important role in the spawning and hatching of fish”, it is repetitive.
Lines 90-91: Change to "rainbow trout Oncorhynchus mykiss at the Colorado River" and to "brown trout Salmo trutta at the Calore Irpino River". Besides, scientific names (Oncorhynchus mykiss and Salmo trutta) in italics.
Line 107: sentence “a fuzzy logic-based Spinibarbus hollandi habitat suitability model” should be rewritten.
Line 109: include the scientific name in italics: Acipenser sinensis.
Line 109: Why "therefore"? I prefer something like "In the same way"
Lines 112-120: rewrite. If you say "This study aimed to:" you have to continue with a verb:
"analyse the influence..." "establish a fuzzy logic...." "study the relationship between..."Lines 121-125: I believe that this paragraph is not necessary
Line 147: change idellus to idella, here and in all the text.
Line 148: correct abbreviation is C. idella. Perhaps you can introduce the common name (grass carp) and use that instead of abbreviation in all the text.
Line 193: revise in all the text, scientific names are in italics, genus (Ctenopharyngodon) the first is upper case word.
Line 199: need references to models.
Line 213: I believe that such doesn't need to extend and detailed explanation about models.
Line 478: This paragraph is more discussion that results, do you think so?
Author Response
Dear reviewer,
Thanks very much for giving us constructive suggestions which would help us to improve the quality of the paper. Here we submit the revised version of our manuscript with the title “Analysis of an ecological flow regime during the Ctenopharyngodon idella spawning period base on reservoir operations”, which has been modified according to the reviewers’ suggestions. If there is any question about this paper, please don’t hesitate to let us know.
Sincerely yours,
Hui Qin, Associate Professor
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The following is a point-to-point response to your comments.
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There are a lot of little mistakes to arrange, and some general issues to resolve. In general, I believe that text is too extensive. Explanations about models and fuzzy logic are very detailed, and it is not necessary. Discussion, in the same way, is very too extensive, you can reduce that.
Answer:
Thank you very much for the comments on the paper. This paper has been reviewed by a reviewer before. At the same time, the reviewer proposed a revision, so you saw the manuscript with the mark. Based on your comments, we have reduced some content of model, fuzzy logic and discussion in this paper.
Some minor changes in the text:
(1) Line 3: scientific names should be in italics. Review that in all the text.
Answer:
Thanks for your suggestion, we use italics to indicate the scientific name in this paper.
(2) Lines 17, 20, 21 26 and 27: avoid the use of abbreviations on the abstract.
Answer:
We removed the abbreviations from the abstract.
(3) Lines 46-47: as support of this, you can use any references as the following paper.
Answer:
Adopted your suggestion, we added references in this sentence. “Furthermore, the resulting discharge process change the river characteristics and related fish habitats quantity and quality [5].”
[5] R. Miranda, J. Martinez-Lage, J. Molina, J. Oscoz, I. Tobes, A. Vilches. Effects of stress controlled loading of a reservoir on downstream fish populations in a Pyrenean river. Environmental Engineering and Management Journal, 2012, 11(6): 1125-1131.
(4) Lines 52-53: this sentence needs a reference.
Answer:
We added references in this sentence. “In recent years, more and more reservoirs have been built. According to statistics, more than 100,000 reservoirs have been built in China with more than 100,000 m3 of storage capacity [7][8].”
[7] Z Feng, W Niu, C Cheng. China’s large-scale hydropower system: operation characteristics, modeling challenge and dimensionality reduction possibilities. Renewable Energy, 2019, 136: 805-818.
[8] J Huang, Y Zhang, G B Arhonditsis, J Gao, Q Chen, N Wu, F Dong, W Shi. How successful are the restoration efforts of China's lakes and reservoirs? Environment International, 2019, 123: 96-103.
(5) Line 55: I am not English native, but I believe that this sentence should be "Fishes are a common indicator".
Lines 62-63: Delete “Water temperature plays an important role in the spawning and hatching of fish”, it is repetitive.
Answer:
We have revised these sentences according to your requirements. “Fishes are a common indicator of aquatic habitat richness.” “Water temperature plays an important role in the spawning and hatching of fish.”
(6) Lines 90-91: Change to "rainbow trout Oncorhynchus mykiss at the Colorado River" and to "brown trout Salmo trutta at the Calore Irpino River". Besides, scientific names (Oncorhynchus mykiss and Salmo trutta) in italics.
Line 107: sentence “a fuzzy logic-based Spinibarbus hollandi habitat suitability model” should be rewritten.
Line 109: include the scientific name in italics: Acipenser sinensis.
Answer:
We have revised these sentences according to your requirements. At the same time, we use italics to indicate the scientific name in this paper.
(7) Line 109: Why "therefore"? I prefer something like "In the same way".
Answer:
Thanks for your suggestion, we change "therefore" to "In the same way".
(8) Lines 112-120: rewrite. If you say "This study aimed to:" you have to continue with a verb:
"analyse the influence..." "establish a fuzzy logic...." "study the relationship between..."
Answer:
We have revised this sentence and change “This study aimed to:” to “The purposes of this study are as follows:”
(9) Lines 121-125: I believe that this paragraph is not necessary.
Answer:
We removed this paragraph from this paper.
(10) Line 147: change idellus to idella, here and in all the text.
Answer:
Thanks for your suggestion, we have made a unified revision to the spelling of Ctenopharyngodon idella in this paper.
(11) Line 148: correct abbreviation is C. idella. Perhaps you can introduce the common name (grass carp) and use that instead of abbreviation in all the text.
Line 193: revise in all the text, scientific names are in italics, genus (Ctenopharyngodon) the first is upper case word.
Answer:
Thanks for your suggestion, we have made a unified revision of the abbreviations of Ctenopharyngodon idella in this paper and changed all of them to C. idella. At the same time, the first letter of the scientific name in this paper is capitalized.
(12) Line 199: need references to models.
Answer:
Adopted your suggestion, we added references in this sentence. “The simulation results of velocity, water depth and water temperature were used to construct a fuzzy model [31][40] to comprehensively analyze the effects of three factors on C. idella spawning.”
[31] P Zhang, Z Yang, L Cai, Y Qiao, X Chen, J Chang. Effects of upstream and downstream dam operation on the spawning habitat suitability of Coreius guichenoti in the middle reach of the Jinsha River. Ecological Engineering, 2018, 120: 198-208.
[40] R Muñoz-Mas, P Marcos-Garcia, A Lopez-Nicolas, F J Martínez-García, M Pulido-Velazquez, F Martínez-Capel. Combining literature-based and data-driven fuzzy models to predict brown trout (Salmo trutta L.) spawning habitat degradation induced by climate change. Ecological Modelling, 2018, 386: 98-114.
(13) Line 213: I believe that such doesn't need to extend and detailed explanation about models.
Answer:
We removed this paragraph from this paper.
(14) Line 478: This paragraph is more discussion that results, do you think so?
Answer:
We removed this paragraph from this paper.
Round 2
Reviewer 1 Report
Thank you for your revision. You make a great improvement. However some issues remain. It is more a moderate revision request than major but the evaluation form did not give the possibilty for a middle value.
Figure 1. – please add scale
Figure 3. – from the text I understood that he fuzzy rule
Figure 5. – did the figure bring something to the paper? It is a usual grid for a hydrological model. Suppress or add legend (blue dot, grey line, grey dot) + scale + north + flow direction
Figure 9. - North and scale
Why Figures 9. and 12 and 13 did not show only the same out-discharge?
Figure 10. Add in the title what is a) b) and c). Use for the three 3D plot the same scales of the axis
Figure 12. – HSI partition is wrong. e.g. 0.18 cannot be dark blue and middle dark blue
Discussion:
In the best case, you have a bit more than 100 000 m² suitable for spawning activities (see WUA graph). But it is interessant to see they distribution. How many of the suitable areas are big enough to support spawning. Fish did not need 100% of the river fitting for spawning, sometimes few m² are enough. Could you please develop on this?
Before speaking about future work, you should discuss the quality of the method. I am working on habitat modelling too but reader expect you to be critic and to question the validity and the robustness of your model. Especially since you did not present a reference site validating the fuzzy rules defined.
Author Response
Dear reviewer,
Thanks very much for giving us constructive suggestions which would help us to improve the quality of the paper. Here we submit the revised version of our manuscript with the title “Analysis of an ecological flow regime during the Ctenopharyngodon idella spawning period base on reservoir operations”, which has been modified according to the reviewers’ suggestions. We mainly revised and improved the figures and discussion section in this paper at this time. If there is any question about this paper, please don’t hesitate to let us know.
Sincerely yours,
Hui Qin, Associate Professor
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The following is a point-to-point response to your comments.
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(1) Figure 1. – please add scale
Answer:
Thanks for your suggestion, we have modified Figure 1 and added a scale.
(2) Figure 3. – from the text I understood that he fuzzy rule
Answer:
According to the requirements of other reviewers, we have added a section (3.1. Model framework). At the same time, a graph of habitat model framework is drawn.
(3) Figure 5. – did the figure bring something to the paper? It is a usual grid for a hydrological model. Suppress or add legend (blue dot, grey line, grey dot) + scale + north + flow direction
Answer:
Figure 5 mainly shows the hydrodynamic model grid framework built using MIKE21. We have added legend, scale, northbound coordinates and flow direction in the figure.
(4) Figure 9. - North and scale
Answer:
Thanks for your suggestion, we have modified Figure 9 and added a scale and northbound coordinates.
(5) Why Figures 9. and 12 and 13 did not show only the same out-discharge?
Answer:
We have added the analysis of the scenarios under different reservoir inflow for the same reservoir outflow. At the same time, the spatial distribution of HSI under different inflow scenarios is shown in Figure 14.
“When the reservoir outflow is 120 m3/s and reservoir outflows are 40 m3/s, 60 m3/s, 80 m3/s, 100 m3/s, 120 m3/s, 140 m3/s and 160 m3/s, respectively, the spatial distribution of habitat suitability index is shown in Figure 14. From the analysis in Figure 13, 120 m3/s is a suitable reservoir outflow. From the results of Figure 14, it can be seen that under this suitable outflow, the larger reservoir inflow will make the overall habitat suitability index better. The larger reservoir inflow makes the water body mix well for the same reservoir outflow, which leads to the decrease of the thermal stratification stability. Therefore, the temperature difference between the reservoir inflow and the outflow is relatively small, which is beneficial to CI spawning. Based on the spatial distribution characteristics of habitats under 7 different reservoir inflow scenarios, the overall suitability is optimal at 160 m3/s. This shows that reservoir inflow has a certain impact on CI spawning. The reservoir inflow provides a space for rational allocation of water resources.”
(6) Figure 10. Add in the title what is a) b) and c). Use for the three 3D plot the same scales of the axis
Answer:
Thanks for your suggestion, we have modified Figure 10 and added subtitles in a), b) and c).
(7) Figure 12. – HSI partition is wrong. e.g. 0.18 cannot be dark blue and middle dark blue
Answer:
Thanks for your suggestion, we have modified and re-colored the figure of Habitat Suitability Index (HSI). (Figure 12-15)
(8) Discussion:
In the best case, you have a bit more than 100 000 m² suitable for spawning activities (see WUA graph). But it is interessant to see they distribution. How many of the suitable areas are big enough to support spawning. Fish did not need 100% of the river fitting for spawning, sometimes few m² are enough. Could you please develop on this?
Before speaking about future work, you should discuss the quality of the method. I am working on habitat modelling too but reader expect you to be critic and to question the validity and the robustness of your model. Especially since you did not present a reference site validating the fuzzy rules defined.
Answer:
Thanks for your suggestion, we added content in the discussion section of this paper (4.4.2. Suitable spawning areas discussion and 4.4.3. Methods discussion).
“4.4.2. Suitable spawning areas discussion
In order to discuss the suitable for CI spawning activity areas, this paper calculates and analyzes the weighted usable area with a suitability of 0.6 or more. The results is shown in the table 4. It can be seen from the table that 1) under the 7 scenarios with low flow, the weighted usable area with a suitability of 0.6 or more is 0; 2) when the reservoir inflow is 100 m3/s and outflow is 160 m3/s, the weighted usable area with a suitability of 0.6 or more is the largest. The maximum value is 135,396 m3, accounting for 62.6% of the total habitat area of the study area; 3) when the reservoir inflow is greater than 60 m3/s and outflow is greater than 100 m3/s, and the CI has more than 100,000 m3 suitable for spawning activity area.
The main spawning area of CI spawning is shown in Figure 15 (Select a scenario where the reservoir inflow is 100 m3/s and outflow is 160 m3/s). According to the survey data, the CI historical sampling points are mainly concentrated in three areas, which is close to the best suitability area of the simulation results. The model has a certain reliability under less data samples and is a better choice.
4.4.3. Methods discussion
In this paper, the fuzzy logic method is used to consider the comprehensive effects of velocity, water depth and water temperature on CI habitat suitability. Finally, the relationship between velocity, water depth, water temperature and weighted usable area was established. Fuzzy logic can solve the problem of information uncertainty in habitat simulation. It can use inaccurate or fuzzy information, and can also represent expert knowledge with preference data sets. However, fuzzy sets and fuzzy rules that rely entirely on expert judgment may be too subjective, lacking reference sites for validation-defined fuzzy rules. The model in this paper also has some room for improvement in terms of accuracy and robustness. However, under the condition of less data samples, it is also a relatively good choice.
At present, research has used measured data to optimize fuzzy sets and fuzzy rules constructed by empirical methods [43]. The data-driven fuzzy logic method is based on the existing measured data to optimize the training based on the fuzzy set and fuzzy rules constructed by experience. The data-driven fuzzy logic method is a certain concern in the habitat simulation evaluation method in recent years, and it is applied to the simulation of habitat suitability of fish in Spanish brown trout [29], China's Chinese sturgeon [45] and so on. On the basis of a certain amount of measured data, the fuzzy rules of this paper can be further modified to improve the validity and robustness of the model. Future research will mainly considers data-driven fuzzy logic.”
[43] E Van Broekhoven, V Adriaenssens, B De Baets, P F M Verdonschot. Fuzzy rule-based macroinvertebrate habitat suitability models for running waters. Ecological Modelling, 2006, 198(1-2): 71-84.
[29] A M Mouton, J D Alcaraz-Hernández, B De Baets, P L M Goethals, F Martínez-Capel. Data-driven fuzzy habitat suitability models for brown trout in Spanish Mediterranean rivers. Environmental Modelling & Software, 2011, 26(5): 615-622.
[45] Y Yi, J Sun, S Zhang. A habitat suitability model for Chinese sturgeon determined using the generalized additive method. Journal of Hydrology, 2016, 534: 11–18.
Reviewer 3 Report
All my suggested changes have been done, and paper is ready to be published in my opinion.
Author Response
Thank you for your comments on the article.
Round 3
Reviewer 1 Report
Good work
Author Response
Thank you for your comments on this paper.
